API Request Builder

What is API Request Builder?

API Request Builder is a browser-based HTTP client that lets you construct, send, and inspect API requests without leaving the browser. It supports all HTTP methods (GET, POST, PUT, PATCH, DELETE, HEAD, OPTIONS), multiple authentication schemes (Bearer, Basic, API Key), request headers, and body formats including JSON, form data, raw text, and binary. Responses are displayed with syntax-highlighted bodies, headers, status codes, and timing information.

Frontend developers testing backend endpoints, API developers iterating on endpoint design, and QA engineers manually verifying API behavior before writing automated tests. The tool runs entirely in your browser — your data never leaves your device.

How to Use API Request Builder

1. Enter the full endpoint URL and select the HTTP method from the dropdown
2. Add headers manually or choose a preset like Content-Type: application/json
3. Configure authentication — Bearer token, Basic auth, or API key in header or query
4. Compose the request body in JSON, form data, or raw format for POST/PUT/PATCH requests
5. Click Send and review the response status, timing, headers, and formatted body

Common Use Cases

• Testing a REST API endpoint during development without switching to Postman or Insomnia
• Quickly sending authenticated requests to verify API key or Bearer token configurations
• Debugging CORS issues by examining preflight OPTIONS request and response headers
• Prototyping API integrations by iterating on request parameters and reviewing responses
• Demonstrating API usage to team members with a sharable request configuration

Pro Tips

• Always set Content-Type explicitly — sending JSON without application/json can cause servers to reject the body or parse it incorrectly
• Check the response timing breakdown to distinguish between DNS resolution, connection setup, and server processing time for performance debugging
• Use the cURL export feature to convert your visual request into a curl command for use in scripts, CI pipelines, or sharing with colleagues

Why Use This Tool?

• Privacy-first: All processing happens locally in your browser. No data is transmitted to any server.
• No installation required: Works in any modern browser on desktop or mobile.
• Completely free: No account, no credit card, no usage caps.
• Fast and reliable: Powered by modern Web APIs for near-instant results.

Related Concepts

Learn more about related topics: REST API, cURL, Postman, OpenAPI.

Frequently Asked Questions